Proton pump inhibitors (PPI) are a class of drugs with the indisputably high effectiveness and a good safety profile. Taking into account the considerable distribution of acid-depending diseases in the modern world PPIs are applied quite widely; the modern practice is unthinkable without them. At the same time one can’t but admit that these drugs are often indicated in lack of justified indications, in unreasonably high dosages and for the excessively long time. In works of the recent time clinicians and pharmacists call on responsible attitude to use of PPIs, especially to “off-label” use – outside official indications; in these cases it’s necessary to prudently justify it the medical documentation.